Amino formaldehyde resins are traditional crosslinkers which have been widely used for waterborne or solventborne coatings for nearly half a century. Coatings crosslinked with amino resins provide good cost-performance efficiency. However, these coating systems involve release of formaldehyde and acid-etching problems. With increasing concerns for the environment and public health, other crosslinkers for waterborne coatings have been developed by the coating industry to alleviate these problems. Typical crosslinkers of this type are aziridines, carbodiimides, oxazolines, epoxies, and silanes. However, waterborne coating systems using these compounds as the crosslinkers still present certain problems, including toxicity, short potlife, slow cure speed, or low cost-to-performance efficiency.
Tris(alkoxycarbonylamino) triazines (hereinafter, "TACT") have been reported to be used as crosslinkers for solventborne coatings (WO 98/27166), water reducible coatings, or carboxylic acid functional aqueous coating binders applied as a base coat followed by a clear top coat through a wet-on-wet and then a bake process to develop a clear crosslinked coating (WO 98/44060).
The present invention is directed to a coating composition comprising an aqueous dispersion or solution of a hydroxyl-functional polymer component and a tris(alkoxycarbonylamino) triazine crosslinker. The polymer component(s) can optionally include carboxyl-functionality as well as hydroxyl-functionality. Further, the coating composition may optionally include catalysts, including Lewis or Bronsted acids, latent acid catalysts and tertiary amines, pigments, flow/leveling agents, dispersants, thickness and other rheology modifiers and/or coalescing agents.